Homogenizers of this sort are utilized for example in the cosmetic, pharmaceutical and chemical industries in the manufacture of creams, salves, pastes and the like. The homogenizer is positioned for example at the lowest point of a container and/or disperses the liquid substance by the fact that the rotor together with a fixed stator applies shearing forces to the substance. The homogenizer could also be placed separately next to a container or between two containers. The homogenized substance can either be transported back into the container or into a filling facility.
In known homogenizers, the homogenization can be influenced mainly by varying the speed of rotation of the rotor with respect to the fixed stator, or by the concrete design of the rotor and/or stator. The shearing effect and also the transporting effect of the homogenizer are greater at high rotational speeds than at lower speeds. A disadvantage of the known homogenizers consists in the fact that the shearing effect and the transporting effect are directly interlinked. Moreover, in order to attain high shearing effects and high rotor speeds it is necessary for the drive mechanisms and drive motors to be of appropriately complex design.
An additional disadvantage consists in the fact that at too high a motor speed the shearing effect becomes so great that the substance which is to be homogenized is affected negatively and can even be damaged.
In order to be able to meet the requirement of high pumping performance (transport effect) while at the same time reducing the shearing effect at high rotational speeds, homogenizers have been developed which allow an axial shift of the rotor relative to the stator, in order to increase the free cross sections of flow (or gaps) between the blades of the rotor and the stator (see DE 296 08 712 and DE 24 13 452). The engineering complexity of such axial shifting ability is very high.